Agree. If he needs tabs to get on plane he probably would not want to take the diffuser ring off. But might be a good idea to check the props. My 2 new B1s from Merc last year were completely different. There was ,9 inch pitch difference between them. One had some cup, but a different amount on each blade. The other had no cup on any blade. One had the points left on the blade tips from the mold. They other had them rounded off. I would never count on stock B1s being close to spec or be identical.

I will call factory , they have been helpful in the past.

Looks like I will have existing props worked and trued up, also I can borrow a friends 28 B1'S to get a fresh base line.

Thanks for every ones input;

Wayne will tell you labbed 28s are the best, so I sent mine to Bblades and I'm at 11% slip. You're not going to get better.